package com.tianze.library.utils;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;

/**
 * base64
 */
public class Base64 {

    static final char[] charTab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
            .toCharArray();

    private Base64() {
    }

    public static String encode(String s) {
        return encodeUTF8(s);
    }

    public static String encodeUTF8(String s) {
        String r = null;
        if (s == null) r = null;
        try {
            r = new String(encode(s.getBytes("UTF-8")));
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            r = null;
        }
        return r;
    }

    public static String encodeGBK(String s) {
        String r = null;
        if (s == null) r = null;
        try {
            r = new String(encode(s.getBytes("gbk")));
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            r = null;
        }
        return r;
    }

    public static String encode(byte[] data) {
        return encode(data, 0, data.length, (StringBuffer) null).toString();
    }

    public static StringBuffer encode(byte[] data, int start, int len, StringBuffer buf) {
        if (buf == null) {
            buf = new StringBuffer(data.length * 3 / 2);
        }

        int end = len - 3;
        int i = start;
        int n = 0;

        int d;
        while (i <= end) {
            d = (data[i] & 255) << 16 | (data[i + 1] & 255) << 8 | data[i + 2] & 255;
            buf.append(charTab[d >> 18 & 63]);
            buf.append(charTab[d >> 12 & 63]);
            buf.append(charTab[d >> 6 & 63]);
            buf.append(charTab[d & 63]);
            i += 3;
            if (n++ >= 14) {
                n = 0;
                buf.append("\r\n");
            }
        }

        if (i == start + len - 2) {
            d = (data[i] & 255) << 16 | (data[i + 1] & 255) << 8;
            buf.append(charTab[d >> 18 & 63]);
            buf.append(charTab[d >> 12 & 63]);
            buf.append(charTab[d >> 6 & 63]);
            buf.append("=");
        } else if (i == start + len - 1) {
            d = (data[i] & 255) << 16;
            buf.append(charTab[d >> 18 & 63]);
            buf.append(charTab[d >> 12 & 63]);
            buf.append("==");
        }

        return buf;
    }

    static int decode(char c) {
        if (c >= 65 && c <= 90) {
            return c - 65;
        } else if (c >= 97 && c <= 122) {
            return c - 97 + 26;
        } else if (c >= 48 && c <= 57) {
            return c - 48 + 26 + 26;
        } else {
            switch (c) {
                case '+':
                    return 62;
                case '/':
                    return 63;
                case '=':
                    return 0;
                default:
                    throw new RuntimeException("unexpected code: " + c);
            }
        }
    }

    /**
     * 解码
     * @param s
     * @param charsetName gbk utf-8
     * @return
     */
    public static String decode(String s, String charsetName) {
        try {
            return new String(decode(s), charsetName);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            return "decode_error";
        }
    }

    public static byte[] decode(String s) {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();

        try {
            decode(s, bos);
        } catch (IOException var3) {
            throw new RuntimeException();
        }

        return bos.toByteArray();
    }

    public static void decode(String s, OutputStream os) throws IOException {
        int i = 0;
        int len = s.length();

        while (true) {
            while (i < len && s.charAt(i) <= 32) {
                ++i;
            }

            if (i == len) {
                break;
            }

            int tri = (decode(s.charAt(i)) << 18) + (decode(s.charAt(i + 1)) << 12) + (decode(
                    s.charAt(i + 2)) << 6) + decode(s.charAt(i + 3));
            os.write(tri >> 16 & 255);
            if (s.charAt(i + 2) == 61) {
                break;
            }

            os.write(tri >> 8 & 255);
            if (s.charAt(i + 3) == 61) {
                break;
            }

            os.write(tri & 255);
            i += 4;
        }

    }

    public static String encodeBase64Url(String s) {
        String r = null;
        if (s == null) r = null;
        try {
            r = encodeUrl(new String(encode(s.getBytes("UTF-8"))));
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            r = null;
        }
        return r;
    }



    public static String encodeUrl(String s) {
//        String afterEncode = null;
//        // % 转义符为 qQ
//        afterEncode = s.replaceAll("\n", "").replaceAll("\\%", "qQ");
//        // # 转义符为 1a
//        afterEncode = afterEncode.replaceAll("\\#", "1a");
//        // 空格 转义符为 + 或 1s
//        afterEncode = afterEncode.replaceAll(" ", "1s");
//        // + 转义符为 da
//        //afterEncode = afterEncode.replaceAll("\\+", "da");
//        // / 转义符为 %2F
//        // afterEncode = afterEncode.replaceAll("\\/", "%2F");
//        afterEncode = afterEncode.replaceAll("\\/", "d6");
//        // ? 转义符为 d5
//        afterEncode = afterEncode.replaceAll("\\?", "d5");
//        // & 转义符为 a9
//        afterEncode = afterEncode.replaceAll("\\&", "a9");
//        // = 转义符为 %3D
//        // afterEncode = afterEncode.replaceAll("=", "%3D");
        return s;
    }
//    public static String encodeUrl(String s) {
//        String afterEncode = null;
//        // % 转义符为 %25
//        afterEncode = s.replaceAll("\n", "").replaceAll("\\%", "%25");
//        // # 转义符为 %23
//        afterEncode = afterEncode.replaceAll("\\#", "%23");
//        // 空格 转义符为 + 或 %20
//        afterEncode = afterEncode.replaceAll(" ", "%20");
//        // + 转义符为 %2B
//        afterEncode = afterEncode.replaceAll("\\+", "%2B");
//        // / 转义符为 %2F
//        // afterEncode = afterEncode.replaceAll("\\/", "%2F");
//        afterEncode = afterEncode.replaceAll("\\/", "@");
//        // ? 转义符为 %3F
//        afterEncode = afterEncode.replaceAll("\\?", "%3F");
//        // & 转义符为 %26
//        afterEncode = afterEncode.replaceAll("\\&", "%26");
//        // = 转义符为 %3D
//        //afterEncode = afterEncode.replaceAll("=", "%3D");
//        return afterEncode;
//    }

}
